var stream=require("stream");
var Readable=stream.Readable;

var code='a'.charCodeAt(0);
function MyReadable(){
    Readable.call(this);
    this._read=function(){
        if(code<='z'.charCodeAt(0)){
            this.push(String.fromCharCode(code));
            code++;
        }else{
            this.push(null);
        }
    }
    this.pipe(process.stdout);
}
MyReadable.prototype.__proto__=Readable.prototype;

var readable=new MyReadable();
